OpenDime is a great way to keep and transfer Bitcoins or Litecoins. It's a USB hardware wallet that you can trade physically, like literally just handing over to someone (or you can keep it like a piggybank). There's no password except the private key, and it can only be unlocked physically. They really put a lot of thought into how it works. The great thing about it is that the wallet's Private Key cannot ever revealed to anybody until a certain part of the device is physically separated (you need to break it off, and it can never be reattached).
That way the next owner can rest assured that the previous owner can never take any coins out of it. The other great thing about OpenDime is that they're so cheap, in fact, they only sell them in 3-packs because it would be a waste of shipping fees to mail out just one. There are two different models of OpenDime, one for Bitcoins and another for Litecoins. At the time of this writing I believe only the Bitcoin version is available at the official online store.
They connect to your computer or mobile device just like a USB Flash Drive. When you plug it into your computer it shows up as a new USB Drive. Once the device has been Initialized you can open the drive on your computer and you'll see an Index.html file, opening that file in your web browser will display the BTC Deposit Address where funds can be added to your OpenDime, it also has a link where you can check how much BTC it has.
To Initialize the OpenDime simply plug it into your computer and then copy some random files onto the OpenDime Drive (at least 256 kilobytes in size), preferably files that are not public because your private key will be randomly generated using the data in those files as the seed for the randomness. Personally, I used a random number generator to create random data for this when I initialized my own Open Dime. Each OpenDime needs to be initialized just once. After being Initialized simply unplug the OpenDime and then plug it back in again. That's when the Index.html file will appear allowing you to see your deposit address, but not your private keys (not yet).
In order to Send or Withdraw BTC to another address or see the OpenDime's private keys you must first physically break the seal on the device by breaking out (with a pin or something like that) the little round part where there's an arrow pointing to it on one side. Removing that part and then plugging the device back into a computer will 'unlock' the OpenDime so that it can be used to send money as well as receive. This is important to understand, you will not be able to send or withdraw any BTC from your OpenDime until after the security lock part is detached from the OpenDime.
But remember, once you have unlocked your OpenDime it will no longer be suitable for physical trades (handing it to someone else to give them money). So you shouldn't unlock it until you're ready to withdraw the funds to another wallet. The OpenDime is only suitable for trading if it has Not Yet been unlocked. If someone offers you an OpenDime, first (in addition to checking the balance) check to make sure that it's lock piece is still in place, otherwise the person who gave it to you could have copied the private keys and then they would be able to withdraw the coins without physically having the device!
Security can be a tricky thing, always be sure to know what you're doing. Luckily, the OpenDime flashes a green LED light when it's Initialized and a red LED light when it's Unlocked.
Here is a link to my OpenDime Wallet (I'm not asking for money, but I can't stop you from being generous either) 19HjGUr8j7t6kQzBDYxK9zzXnGFJ8XUo3M this is to let you see the interface from the Check Balance page, and also to show how much I trust OpenDime's security (try to hack my wallet, go ahead I dare you, lol). There's also a link at the bottom of that page where you can buy your own OpenDimes from their online store if you want.